Garden Talk: July 20, 2006

From NGA Editors

Poison Ivy Gets Pumped Up

One of the scourges of summer is dermatitis from contact with poison ivy. The leaves, branches, and roots of this perennial vining weed contain an oil (urushiol) that, once it penetrates your skin, can cause itching and scratching for weeks. Worse yet, the oil remains active on clothes, tools, and gloves and can reinfect you even when youre not working in the garden.

As if poison ivy isn't bad enough already, researchers from the Marine Biological Laboratory in Woods Hole, Massachusetts, predict that due to increased carbon dioxide levels in the atmosphere, poison ivy will be growing even bigger and faster. For the past six years, researchers have monitored poison ivy plants growing with present CO2 levels and those given artificially increased levels to mimic future predictions. They have found that poison ivy with high CO2 levels doubled its growth rate and produced more of the pain-inducing oil than control plants.

Researchers suspect that all woody vines can put the increased CO2 to use in producing more leaves and vines because they don't have trunks or other supports that need a share of the carbon.

The First True Red Hydrangea

One visit to your local garden center and its clear that mophead hydrangeas (Hydrangea macrophylla) are very popular. While pink or blue flowers have been the most popular colors, plant breeders also have been working on new red selections. Up until now, most red hydrangeas have produced flowers that are more lavender or deep pink. However, Hornli breaks the mold. Hydrangea macrophylla Hornli produces fire engine red flowers on a dwarf plant that's perfect for a container or flower garden. Hornli grows only 2 feet tall and wide and produces 3-inch-diameter blooms on old wood, so it will need protection in colder areas. Its hardy in USDA zones 6 to 9.

Veggies Help Prevent Clogged Arteries

Its common knowledge that eating vegetables is good for us, and a recent study helps us understand at least one reason why. In laboratory tests on rodents, researchers at Wake Forest University School of Medicine found that mice given a diet including vegetables, particularly peas and carrots, had healthier arteries compared to mice with no vegetables in their diets.

One half of the mice received 30 percent of their calories from vegetables, while the other half received no vegetables. After 16 weeks researchers measured cholesterol to estimate the extent of atherosclerosis (plaques in the artery walls) and found that the fatty deposits in the arteries of mice that had eaten vegetables were 38 percent smaller. This is the first study to suggest that eating vegetables may reduce atherosclerosis and prevent strokes and heart attacks.

Add Water-Absorbing Gel After Planting

Water-absorbing crystals are often used to keep containers, hanging baskets, and pots moist during dry summer weather. The traditional way to apply the crystals is to mix them into the potting soil before you plant. Every time you water, the gel contained in the crystals absorbs moisture and expands. The gel slowly releases water over time, keeping the soil moist longer and requiring you to water less.

But what happens if you are so busy in spring you forget to mix in the crystals? A new product will help you add gel to the potting soil even after planting. The Gel-Jector is a caulking-sized tube filled with water-absorbing gel. Using a caulking gun, you simply inject the gel 4 inches deep into the container and let it work its magic. Use 4 trigger squeezes for a 12-inch-diameter container.